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Hawkins Electrical Guide

The Hawkins Electrical Guide was a technical engineering book published in 1917, intended for the common man to understand highly complex principles of every manner of electric device. The book is notable for the extremely high number of detailed illustrations it contains, and the small softbound size of the volumes.

The book was published by Theodore Audel & Company, and the majority of the illustrative content became the basis of decades of followup books published under the Audels brand name. The illustrative content of these books can still be found in Audels books sold new today.

Because the Hawkins Electrical Guide was printed in the United States prior to 1923, the content of the books has passed into the public domain.

Free media access on the Internet

Due to several book digitizing initiatives such as the Gutenberg project many of these older public domain books are becoming available on the Internet. This series of books is currently available for free, non-commercial use from Google Books and each volume can be downloaded as a PDF, though the illustration scan quality is not as good as the ones being added to Wikipedia on this page by Wikipedia contributors.

Google Books Volume Links

As of September 2008, Google Books does not provide a simple, direct means to find each volume of this media set, and appears to include scanned copies of different volumes from different libraries and copyright dates from 1914-1917. Scan quality varies from one volume to the next. For your convenience, links to the available scanned media are provided here:

Volume 1, Copyright 1917, Impression 1921, from the University of California

Volume 2, Copyright 1917, from the University of Wisconsin - Madison, General Library System

Page 175, Figure 183Main Wikipedia article: Gramme machineDescription: A one pole, two coil Gramme ring. The second coil is wired in series with the first and the voltage of both is added together.

Page 177, Figure 185Main Wikipedia article: Gramme machineDescription: A four coil Gramme ring. The coils of A and A' sum together as do the coils of B and B', producing two pulses of power 90 degrees out of phase with each other. When coils A and A' are at maximum output, coils B and B' are at zero output.

Page 178, Figure 186Main Wikipedia article: Gramme machineDescription: A three pole, six coil Gramme ring, and a graph of the combined three poles, each 120 degrees out of phase from the other and summing together.

Chapter 15: Classes of Dynamo

Page 183Main Wikipedia article: Excitation (magnetic)Description: A self-excited shunt-wound DC generator is shown on the left, and a magneto DC generator with permanent field magnets is shown on the right. The shunt-wound generator output varies with the current draw, while the magneto output is steady regardless of load variations.

Page 196Main Wikipedia article: Excitation (magnetic)Description: A separately excited DC generator with bipolar field magnets. Separately excited generators like this are commonly used for large-scale power transmission plants. The smaller generator can be either a magneto with permanent field magnets or another self-excited generator.

Chapter 17: The Armature

Page 223Main Wikipedia article: Gramme machineDescription: Early form of the Gramme ring armature with coils penetrating the interior of the ring.

Page 224Main Wikipedia article: Gramme machineDescription: Modern design of the Gramme ring, wrapped only around the exterior of the core.

Page 225Main Wikipedia article: Gramme machineDescription: Diagram of magnetic lines through a Gramme ring, showing the very few magnetic lines of force crossing the center gap.

Page 226Main Wikipedia article: Gramme machineDescription: Example of a single winding around the exterior of a drum core with no wires penetrating the interior.

Chapter 19: Theory of the Armature

Page 264Main Wikipedia article: Commutator (electric)Description: Exaggerated example of how the field is distorted by the rotor.

Page 265Main Wikipedia article: Commutator (electric)Description: Iron filings show the distorted field across the rotor.

Page 281Main Wikipedia article: Field coilDescription: Field lines of a four-pole stator passing through a Gramme ring or drum rotor.

Chapter 20: Commutation and the Commutator

Page 284<Main Wikipedia article: Commutator (electric)Description: In a dynamo, the contact point of where a pair of brushes touch the commutator is referred to as the commutating plane. In this diagram the commutating plane is shown for just one of the brushes.

Page 285Main Wikipedia article: Commutator (electric)Description: Centered position of the commutating plane if there were no field distortion effects.

Page 286Main Wikipedia article: Commutator (electric)Description: Actual position of the commutating plane to compensate for field distortion.

Page 301, Figure 328Main Wikipedia article: Electrical generatorDescription: Dynamos are no longer used for power generation due to the size and complexity of the commutator needed for high power applications. This large belt-driven high-current dynamo produced 310 amperes at 7 volts, or 2,170 watts, when spinning at 1400 RPM.